The invention relates to methods for producing particles of metal vanadium oxide powders through laser pyrolysis. In particular, the invention relates to the use of laser pyrolysis for the production of nanoscale metal vanadium oxide particles. The invention further relates to batteries with improved performance that incorporate nanoscale metal vanadium oxides particles, such as silver vanadium oxide particles.
Lithium based batteries have become commercially successful due to their relatively high energy density. Suitable positive electrode materials for lithium based batteries include materials that can intercalate lithium atoms into their lattice. The negative electrode can be lithium metal, lithium alloys or compounds that can reversibly intercalate lithium atoms into their lattice. Batteries formed from lithium metal or lithium alloy negative electrodes are referred to as lithium batteries while batteries formed with an anode (negative electrode) active material that can intercalate lithium ions are referred to as lithium ion batteries.
In order to produce improved batteries, various materials have been examined for use as cathode (positive electrode) active materials for lithium based batteries. A variety of materials, generally chalcogenides, are useful in lithium based batteries. For example, vanadium oxides in certain oxidation states are effective materials for the production of positive electrodes for lithium based batteries. Also, metal vanadium oxide compositions have been identified as having high energy densities and high power densities, when used in positive electrodes for lithium based batteries. Silver vanadium oxide has a particularly high energy density and high power densities, when used in lithium based batteries. Silver vanadium oxide batteries have found particular use in the production of implantable cardiac defibrillators where the battery must be able to recharge a capacitor to deliver large pulses of energy in rapid succession, within ten seconds or less.
In a first aspect, the invention pertains to a method for producing metal vanadium oxide particles comprising reacting a reactant stream comprising a vanadium precursor, and a second metal precursor in a reaction chamber. The reaction is driven by energy absorbed from an electromagnetic field.
In another aspect, the invention pertains to a battery comprising a cathode having active particles comprising silver vanadium oxide and a binder. The positive electrode exhibits an specific capacity of greater than about 340 milliampere hours per gram of active particles when discharged to about 1.0 V.
In addition, the invention pertains to a battery comprising a cathode having active particles comprising metal vanadium oxide and a binder, the positive electrode exhibiting an specific capacity of greater than about 400 milliampere hours per gram of active particles when discharged to about 1.0 V.
In a further aspect, the invention pertains to an implantable defibrillator comprising a battery having a cathode comprising silver vanadium oxide with an specific capacity upon discharge to about 1.0V of greater than about 340 milliampere hours per gram of cathode active material.
Moreover, the invention pertains to a method of producing a composite of elemental metal nanoparticles and vanadium oxide nanoparticles, the method comprising reacting a reactant stream comprising a vanadium precursor, and a second metal precursor in a reaction chamber, where the reaction is driven by energy absorbed from an electromagnetic field.
In another aspect, the invention pertains to a method for producing metal vanadium oxide particles comprising reacting a reactant stream comprising a vanadium precursor, and a second metal precursor in a reaction chamber, where the reaction is driven by energy absorbed from a combustion flame.
In an additional aspect, the invention pertains to a collection of particles comprising elemental metal selected from the group consisting of copper, silver, and gold, the particles, the collection of particles having an average particle size less than about 500 nm, and effectively no particles have a diameter greater than about four times the average diameter.
In addition, the invention pertains to a method of producing particles comprising a an elemental metal selected from the group consisting copper, silver and gold, the method comprising reacting a molecular stream in a reaction chamber, the molecular stream comprising a metal precursor and a radiation absorber, where the reaction is driven by electromagnetic radiation.